The present invention is deemed to be a considerable and meritorious improvement over the inventions disclosed in U.S. Pat. No. 4,022,479, and U.S. Pat. No. 4,114,902.
It bears reiteration at this juncture to state that in most industries, it is extremely important that there be provided a seal for bearings that supports rotating shafts which prevent the lubricants associated with the bearings from leaking externally of an associated housing or bearing support and for preventing foreign particles in the environment while the shaft is being used from working themselves through the seal and into the lubricant for the bearings.
U.S. Pat. No. 4,022,479 incorporates a disclosure wherein there is taught a sealing ring structure which has as an object, the elimination the movement of the lubricant from the bearings outside of the housing. The sealing ring structure as disclosed, also assists in eliminating the movement of foreign particles into the bearing area and lubricant area within the housing.
It was therein disclosed a sealing structure that is composed of two rings, preferably metal, one of which is fixed to the housing and the other of which is fixed to rotate with the shaft. The ring that is fixed to the housing has a labyrinth-type of seal against the shaft which discourages the lubricant from moving outside of the housing along the shaft. In U.S. Pat. No. 4,022,479, a joint was provided between the two rings which is composed of an annular recess in the first ring that opens axially outwardly of the housing and an annular flange on the adjoining outer ring that fits within the aforementioned annular recess of the first ring. The construction of the annular recess and the annular flange were said to be constructed so that the two bearing rings that are rotating relative to one another, will tend not to bind or create a heated frictional disposition between them. There was also provided in the first sealing ring a hole that communicates to the aforementioned recess. In the embodiment taught in this prior patent, the annular flange of the second sealing ring had notches cut therein. With such an arrangement, foreign particles that moved into the joint formed by the recess and flanges were scraped by the notches in the flanges to the hole where they were discharged back into the atmosphere or the area surrounding the housing. It will be noted that the first ring is, of course, fixed to the housing and the second ring is, of course, adapted to rotate with the shaft by suitable sealing means. However, in both instances, there is no movement between the respective sealing rings and the portion it is fixed to which would normally create wear if the opposite occurred.
The invention of U.S. Pat. No. 4,114,902 was an ingenious improvement over the device disclosed in U.S. Pat. No. 4,022,479. The improvement, among other items included the use of at least one groove on the mating flange with respect to the recess on the other complementary ring. Additionally, the inwardly facing wall of the recess also contained at least one groove. It was noted in U.S. Pat. No. 4,114,902 that these grooves act to inhibit particle migration, regardless of relative peripheral speed of the rotating rings and provide a circumferential path for the exclusion of foreign particles even in the event of zero relative rotation.
Although the above advances have solved a great number of problems, a few problems are still encountered in various particular work applications. For example, liquid lubricants (particularly synthetics) that astringently adhere to the rotating bearing shaft are problematic. In addition, difficulties arise when large quantities of liquid lubricants are propelled at the shaft/stator ring junction as is the case with double reduction gearing as well as pinion and gear interface in speed reduction gearing. Lastly, axially displacement of a round expulsion orifice, located on the radially exterior surface of the first ring and radially communicating with the annular recess, is occassionally rendered ineffective due to the relative axial displacement of the two rings.
Accordingly, it would be highly desirable to have a sealing ring structure that eliminates these residual problems.